Improvement in locks



UNITED STATES PATENT OFFICE.

JOHN M. PERKINS, OF CLEVELAND, OHIO.

IMPROVEMENT IN LOCKS.

Specilication forming part of Letters Patent No. 37,240, dated December 23, usb2.

To all whom it may concern:

Beit known that I, J. M. PERKINS, of Cleveland, in the county of Cuyahoga and State of Ohio, have invented new and useful Improvements in Locks; and I do hereby declare that the following is a full and complete description of the construction and operation of the the same, reference being had to the accompanying' drawings, making part of this speciiication, in which- Figure 1 is a view of the inside of the lock, with the bolt shoved in. Fig. 2 is a view of the inside of the lock, with the bolt shoved out. Fig is a section ofthe lock, viewed from above downward from the line frm, Fig. l. Fig. 4 is a section, looking` upward from the line or' m', Fig. l; and Fig. 5 is an inside view, with the bar of the bolt removed for the purpose of better showing parts not otherwise brought into view.

The nature of my invention relates to such a construction ot' a lock that it cannot be picked or opened, except by the use of the proper key, the same being additional improvements to a lock for which a patent was granted to me under date of August 5, 1862.

A represents the bolt. In Figs. l and 5 it is represented as drawn back within the cas ing of the lock.

B represents the outside keyhole, and G is the recess in the bar of the bolt into which the nib of the key ts in the act of shoving the bolt when the key is placed in the keyhole B. The bolt in this case is shoved forward only to the line A in Fig. 2. Immediatel y behind the bar ofthe bolt, lookingfrom within, as seen in Fig. 3, are shown two parallel guard-plates, D D', which are pivoted to the front plate of the lock-case, as seen at E in Fig. 5. The guard-plate D' is furnished with a stop, F, which falls into one ot' the notches F in the bar of the bolt A, iu which it is held by the spring G, and the bolt cannot be moved backward or forward without lifting the stop out of the notch in which it rests. This is accomplished by means of a depression in the nib of the key, but having only sufticient depth to raise the stop F out of the notches F'. The plate D, which in form is like the plate D', and pivoted at the same point, occupies a position outside of the plate D', and, like its fellow, is pressed downward by a sprin 0*, G'. The curves in the two plates from H to H' correspond, but from H to H the curve in the plate D is greater than in D', as seen in Fig. 5. There is a stop, I, secured to the lower edge of the plate D, which stop is pressed upon the support 1' by the spring G', and there being two notches, J J', in the under edge of the bar ofthe bolt A, it follows that if both the guard-plates D and D' are raised by the nib ofthe key while the stop F is lifted the stop I passes into one of the notches, J or J', which eft'ectually prevents the bolt from moving by the action ot the key; but these guard-plates D D are so connected that an upward moven'ient of the plate D carries with it the plate D'. Consequently either the stop F or I must fall into the notches F' F" F" or J J'. lt will be readily seen that any attempt to pick this lock, constructed as thus far described, would not be likely to become successful, and any attempt to get an impression from the inside would only lead to confusion, because the plates D D' would give but one impression. The plates D D' may be increased to three or more, and placed upon one or both sides of the bar of the bolt; but there are other safeguards, which I will now proceed to describe.

K represents a pivoted guard placed transversely to D D'. The point of articulation is seen at K'. The upper end is pressed back ward by the spring G. At K" there is a stop which projects toward the front plate of the lock, and which falls into a notch in the upper side of the bar of the bolt. Upon the slightest movement ofthe guard in the direction of the arrow the stop at K" is pressed into the notch in the upper side of the bar, and thus prevents the bolt from being shoved back. Wards are arranged along the under surface of the angle a, and the key is iitted thereto, and the least variation in the key will baffle any attempt to shove back the bolt, for the guard K would be pressed back, and the stop K" would fall into the notch fitted to receive it, and consequently the bolt could not be moved, even if all the other points had been overcome.

This lock is also provided with two keyholes, one for the outside and one for the inside of the door. The inside keyhole is shown at B', and the outside one at B. The former, B', is

placed nearer to the bolt than the latter, B, constructed, arranged, and operating as and and the bolt being,` provided with :i plate, L, for the purpose described. which covers the key-hole B when the door is 2. The guard K, the stop K, and the wards locked from the inside, so that dwellings, a, arranged and operated '.is and for the purstores, &c., when provided with this lock, may pose specified. be considered :is proof against burglary.

What I claim as my improvement, and de- Witnesses: sire to secure by Letters Patent, is- W. H. BURRIDGE,

1. The guardplates D D and stops F I, J. BRAINERD.

JNO. M. PERKINS. 

